Abstract
This article shall explore the characteristics of hydro-mechanical transmission in power shift. Based on the double brakes overlapping, the adjustment of the displacement ratio of variable-displacement hydraulic component is considered, and then a new full power shift method is proposed. Models respectively for speed, torque, and power in the power shift process are built. The ideal power shift timing is deduced, with the ratio between speed of fixed-displacement hydraulic component and input speed being the criterion. By combining theoretical analysis and experimental studies, it shows that in power shift process by regulating the displacement ratio of variable-displacement hydraulic component, the interchange between high- and low-pressure sides in closed hydraulic circuit can be completed, and power transition can be thus realized. A new full power shift method is put forward, in which the shift process is divided into five stages: current range, prior stable stage, power transition stage, post stable stage, and target range. Experiments on full power shift process prove that the full power shift method is not only feasible but also can remove the rotational speed fluctuation in power shift process and realize normal full power transmission of output power.
Highlights
Hydro-mechanical variable transmission (HMT) is a kind of double power flow transmission system constituted by hydraulic branch and mechanical branch in parallel.[1]
The rotational speed of fixed-displacement hydraulic component in hydraulic transmission unit attains variable changes with the adjustment of displacement ratio of variable-displacement hydraulic component and achieves stepless speed changing in range after converging speed with the mechanical transmission component
For the HMT working at current range, when the ideal power shift timing comes, the target range brake would be engaged with zero speed difference
Summary
Hydro-mechanical variable transmission (HMT) is a kind of double power flow transmission system constituted by hydraulic branch and mechanical branch in parallel.[1]. In power shift process, during the double brakes overlapping, if the closed hydraulic circuit has different pressures, the torque and power characteristics of HMT would be different.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
